ĐỀ THI OLYMPIC TIẾNG ANH LỚP 10 NĂM HỌC 2013 VÒNG 18 – ĐỀ SỐ 1 Chọn câu trả lời tốt nhất cho những câu hỏi dưới đây. 1. Which number is rational? A. π B. π / 2 C. √21 D. √25 E. √12 2. The graph shows the number of computers infected with a virus at one company over time. Which statement is true about the function that relates number of infected computers to time? A. It is linear with a positive slope. B. It is linear with a negative slope. C. It is nonlinear and always increasing. D. It is nonlinear and always decreasing. E. None of them 3. A journalist is researching customer satisfaction among car owners. He decides to survey a random selection of car owners. Which of the following is the best method of getting a random selection of car owners? A. wait outside a new car dealership and survey new owners B. get a list of customers from a local mechanic C. put an ad in the car section of the newspaper requesting participants D. get a list of car owners from the state department of motor vehicles E. None of them 4. The instructions for a painter’s ladder indicate the following: For the ladder to be at the proper angle with the ground, the distance from the bottom of the wall to the bottom of the ladder should be one-fourth the length of the ladder. Which equation could be solved to find the measure of the angle that the ladder should make with the ground? A. cos A = 4 B. cos A = 1 / 4 C. sin A = 4 D. sin A = 1 / 4 E. sin A = 1 / 3 5. Since 1994, the Winter Olympics have been held in even-numbered years that are not divisible by 4. If this pattern continues, in which of the following years will a Winter Olympics be held? A. 2015 B. 2020 C. 2034 D. 2040 E. 2050 6. A restaurant uses tables shaped like trapezoids. The chart shows the number of people that can be seated when 1, 2, and 3 tables are put together in a row. Based on the pattern shown in the chart, which expression gives the number of people that can be seated in a row of n tables? A. n B. n + 3 C. 4n + 3 D. 3n + 2 E. 2n 7. Which list shows the numbers 1.2, 5 / 4 , 7 / 6 , and 7 / 8 in order from least to greatest? A. 7 / 8 , 5 / 4 , 1.2, 7 / 6 B. 7 / 8 , 7 / 6 , 1.2, 5 / 4 C. 5 / 4 , 7 / 8 , 1.2, 7 / 6 D. 5 / 4 , 7 / 8 , 7 / 6 , 1.2 E. 1.2, 7 / 8 , 5 / 4 , 7 / 6 8. The figure shows ΔABC on the coordinate plane. What are the coordinates of the image of point A after the triangle is reflected over the y-axis? A. (3, 6) B. (6, –3) C. (–6, –3) D. (–6, 3) E. (–6, 13) 9. In the figure, lines l and m are parallel. Which pair of triangles must be similar? A. ΔABD and ΔCED B. ΔABC and ΔBCE C. ΔBCD and ΔABD D. ΔECD and ΔBCD E. ΔEAD and ΔBCD 10. The surface area, S, of a sphere with radius r is given by the formula S = 4πr 2 . The radius of a basketball is 6 times the radius of a Ping-Pong ball. How many times greater is the surface area of the basketball than the surface area of the Ping-Pong ball? A. 3 B. 6 C. 12 D. 36 E. 45